A207244 Number of 4Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 0 vertically

9, 81, 287, 987, 2884, 7165, 17929, 40646, 90602, 196548, 412733, 859077, 1751887, 3532169, 7052859, 13932019, 27335037, 53236611, 103050502, 198448577, 380245761, 725544748, 1379004108, 2611731954, 4930796893, 9281596371

Offset

1,1

Comments

Row 4 of A207242

Links

R. H. Hardin, Table of n, a(n) for n = 1..210

Formula

Empirical: a(n) = 5*a(n-1) -4*a(n-2) -12*a(n-3) +3*a(n-4) +47*a(n-5) -17*a(n-6) -66*a(n-7) -9*a(n-8) +90*a(n-9) +2*a(n-10) -33*a(n-11) +a(n-12) -5*a(n-13) -44*a(n-14) +19*a(n-15) +52*a(n-16) -16*a(n-17) -7*a(n-18) -3*a(n-19) +a(n-20) -18*a(n-21) +17*a(n-22) -2*a(n-23) +2*a(n-24) -3*a(n-25) +3*a(n-26) -3*a(n-27) +a(n-28)

Example

Some solutions for n=4
..0..0..1..0....1..0..0..1....0..1..0..1....1..1..1..1....0..1..0..0
..0..1..0..0....0..1..0..1....0..0..1..0....1..1..1..1....0..0..1..0
..0..1..0..0....1..1..0..1....0..0..1..0....1..1..1..1....0..0..1..0
..0..1..0..0....1..0..0..1....0..0..1..0....0..1..0..1....0..0..1..0

Crossrefs

Sequence in context: A207238 A207496 A208165 * A207064 A207119 A207399

Adjacent sequences: A207241 A207242 A207243 * A207245 A207246 A207247

Keyword

nonn

Author

R. H. Hardin Feb 16 2012

Status

approved